[MacDV] imovie fx

[Robert Green]

I am running imovie 6.0.3 on an intel core duo imac using 10.4.11.  
Whenever I apply an effect to a video or still clip the clip appears  
black after it is applied and when it is played, not only does it not  
appear but the timeline shifts out of sync. The video that is played  
is not in sync with what the timeline shows. The two effects that I  
tried were slow motion to a video clip and the ken burns effect to a  
still. Both resulted in the same problem. Any ideas for a solution?
Rob